Centrifugal self-cleaning snagger



Sept. 28, 1965 J. R. M. CROISETIERE 3,208,680

CENTRIFUG'AL SELF-CLEANING SNAGGER Filed Sept. 25, 1963 5 {:izn

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O a 2/ o o q O 20 X INVENTOR J. R. MARCEL CROISETIERE ATTORNEYS.

United States Patent 3,208,680 CENTRIFUGAL SELF-CLEANING SNAGGER Joseph R. M. Croisetiere, Montreal, Quebec, Canada, assignor to Northern Electric Company Limited, Montreal, Quebec, Canada Filed Sept. 23, 1963, Ser. No. 310,579 Claims. (Cl. 242-25) This invention relates to snagger plates for use with strand take-up mechansims.

This invention has particular applicability to industrial processes for the continuous production of strand in which strand is wound in predetermined lengths on successive take-up reels, the strand being shifted from a full reel to an empty reel without interruption of the process or the flow of strand. The transfer of the strand trom one reel to the other is accomplished by rotating a pair of take-up reels in a strand take-up apparatus in close side by side relationship and by guiding the strand from the full reel to the empty one. Snagger plates with peripheral snagging members or teeth form part of the strand take-up apparatus and are mounted adjacent each reel, between the two reels, for rotation therewith. A strand is thus snagged and retained by a tooth on each snagger plate as it is transferred from one reel to the other. A cutting blade positioned between the snagger plates severs the strand to separate the part on the full reel from the part being wound on the empty reel whereby to enable the full reel to be stopped, removed and replaced by an empty reel in preparation for the next transfer which will occur when the other reel is full. Retention of the one severed strand end by the tooth of the snagger plate associated with the full reel is maintained until that reel is removed while the tooth on the other snagger plate continues to retain the other severed strand end to apply tension to it and facilitate the winding operation.

As the snagger plates are permanent components of the strand take-up apparatus it is important that they release the severed strand end of a full take-up reel when this reel is brought to a stop to permit the removal of the full reel and its replacement by an empty reel. Previously the strand end had been removed from the snagging member by hand. However, the demand for automation in strand producing processes called for the development of self cleaning snagger plates which would consistently release the severed strand end on a full reel when the full reel came to a stop. It is extremely important that the release of the severed strand end on the full reel be effected without fail every time the full reel comes to a stop and is ready for replacement by an empty reel, otherwise the continuous nature of the process would be destroyed or a workman would have to be employed to release the strand end when the snagger plate failed to release it automatically.

A known type of snagger plate, designed to automatically released the severed strand end on a full reel when it comes to a stop, comprises a circular plate with a peripheral flange thereon. A plurality of snagger teeth are mounted on the circular plate, each tooth having a leading portion projecting outwardly of the flange, a trailing portion projecting inwardly of the flange and a central connecting portion extending through an over-sized slot in the flange and pivotally mounted on the circular plate. The trailing portion of the tooth is weighted and spring biased away from the flange and toward the center of the plate. When the reel is at rest the spring forces the trailing portion towards the center of the plate and causes the leading portion to pivot outwardly from the flange to open the tooth and release any strand retained by it. When the reel is rotating the centrifugal force acting on the weighted trailing portion causes this portion to move 3,208,680 Patented Sept. 28, 1965 outwardly toward the inside face of the flange and the leading portion to pivot inwardly towards the outside face of the flange whereby to form a wedge shaped space between the leading portion and the outside face of the flange to trap and retain a strand therebetween.

This type of snagger plate is deficient in at least two important respects. One such deficiency arises from the fact that the slot in the flange through which the middle portion of the tooth extends must be larger in size than this portion of the tooth to permit the tooth to pivot between open and clamping positions. Thus, when the tooth is in clamping position, a portion of the slot is open and there is the danger that foreign matter (particularly the free end of severed strands) will become wedged in the open portion causing the tooth to jam and preventing the tooth from pivoting to open position when the reel stops rotating. If this happens, the clamped strand end will not be released and the automatic removal of the reel cannot be effected, with the result that the continuity of the winding operation, and the strand producing process, must be interrupted.

Another deficiency in the conventional type of snagger plate discussed above arises from the high stresses produced in the snagger tooth as a results of the centrifugal force acting on the weighted trailing portion forcing the leading portion against the outside face of the flange or against the wire trapped between the leading portion and the flange. This high stress is apt to give rise to a high incidence of breakage of the teeth, the broken parts of which are thrown outwardly under the action of centrifugal force to constitute a hazard to workmen in the vicinity of the strand take-up apparatus.

I have found that the deficiencies in the prior art may be overcome in accordance with this invention by providing a snagger plate for strand take-up apparatus comprising a snagging member rigidly secured to said snagger plate, a part of said snagging member extending beyond and overlying a portion of the periphery of said snagger plate, and a jaw member supported on said snagger plate and movable toward and away from said part of the snagging member between a first limiting position beyond the periphery of said snagger plate and distant from said part of the snagging member less than the diameter of a strand to be snagged, and a second limiting position distant from said part of the snagging member greater than the diameter of a strand to be snagged.

The movable jaw member, according to the invention, slides toward and away from a fixed tooth, thus, when the snagger plate is provided with a peripheral flange which is slotted to permit the fixed tooth and movable jaw member to pass therethrough, the area of the slots in the flange on the snagger plate may correspond with the cross-sectional area of the fixed tooth and jaw member so that the slots are substantially entirely occupied by these members during rotation of the snagger plate, leaving no gaps for the entrance of any foreign matter. As a result, the snagger tooth cannot jamb and the automatic release of the severed strand end on a full reel is consistently achieved. In addition, the movable jaw member need not come into contact with the portion of the tooth projecting outwardly from the flange, with the result that this portion of the tooth, (which is the weakest), will not be unduly stressed and, if any portion is stressed, it will be within the flange so that any broken parts will not be thrown out to endanger workmen in the area.

In drawings which illustrate embodiments of the invention,

FIG. 1 is a schematic view of a simplified strand takeup mechanism using snagger plates;

FIG. 2 is a side view of a snagger plate according to the invention;

FIG. 3 is a section along the line III-III of FIG. 2; and

FIG. 4 is a cross-section along the line IV1V of FIG. 2 showing a detail of the snagger plate construction.

In the simplified strand take-up mechanism shown in FIGURE 1, a pair of take-up reels 1 and 2 for a strand 3 are rotatably mounted on arbors 4 with a pair of snagger plates 5 mounted therebetween for rotation therewith in the direction indicated by arrows A. As it is advanced from a processing station the strand 3 is distributed back and forth between the flanges of reel 2 by a strand guide 6 until the reel is full. The strand guide 6 then shifts to the empty reel 1 drawing the strand 3 over the flanges of the reels and across the peripheries of the snagger plates 5 where it is gripped by a snagging member 7 on each snagger plate. A knife 10, positioned between the snagger plates, cuts the strand 3 so the full reel 2 may be stopped and removed from its arbor while the empty reel 1 continues to rotate. The snagging members 7 firmly grip the strand to prevent premature unwinding from the full reel 2 when the strand is cut and to provide sufl'lcient tension to initiate winding of the strand onto the empty reel 1.

The snagger plate of the present invention is depicted in FIGURES 2 and 3 and comprises a circular plate portion 11 having a raised hub 12 centrally thereof and a peripheral flange 13. The raised hub has a central bore 14 therein to accommodate an arbor and a number of peripheral holes 15 to permit the attachment of the snagger plate to said arbor, such that a flange 18 of a take-up reel is in close proximity to said snagger plate. The peripheral flange 13 has a plurality of slots 16 therein spaced at regular intervals, each slot to accommodate a snagger tooth and a movable jaw member to be more fully described.

Rigidly afiixed to circulate plate 11 as by rivets 17, and extending through slots 16 are a plurality of snagger teeth indicated generally by the reference numeral 20. The snagger teeth are provided with a shoulder 21 for abutment against the inner surface of flange 13 adjacent one end of slot 16 and with a guide face 22 and an abutment surface 23. The guide face 22 is generally radially disposed with respect to circular plate 11 and the abutment surface 23 is normal thereto. The portion of the tooth extending outwardly of flange 13 overlies a portion of the flange and has an inner strand engaging face 24. This portion of the tooth diminshes in depth towards its outer free end and curves in a direction parallel to the axis of and towards circular plate 11 as indicated at 25.

Jaw member is mounted on circular plate 11 by means of slot 26, screw 27 and lock-nut (to be described more fully in conjunction with FIGURE 4 for sliding movement on plate 11 generally radially thereto. Jaw member 30 is generally L-shaped having a strand engaging face 31, a guide face 32 and an abutment surface 33. The abutment surface 33 is formed at an enlarged part of the jaw member so that the thickness of the jaw member at the abutment surface is greater than the thickness of the jaw member at the guide face.

In the enlarged portion of the jaw member is a bore 34, counterbored at 35 to slidably receive a coil spring 36 and a plug 37 therein. Plug 37 has an enlarged head 38 adapted to slidingly fit within counter-bore 35 of bore 34. The jaw is so dimensioned that when abutment surfaces 23 and 33 are in contact, strand engaging face 31 is at a distance from the inner strand engaging face 24 of tooth 20 somewhat less than the diameter of a strand to be snagged, and when the outer end of slot 26 is in contact with guide screw 27 strand engaging face 31 is within the outer periphery of the flange 13.

In FIGURE 4 the attachment of the jaw member 31 to plate 11 is shown in detail. Guide screw 27, having threaded portion 40, projects through plate 11 and slot 26 in jaw member 30. Slidably mounted on guide screw 27 is a flanged bushing 41 having a diameter slightly less 4 than the width of slot 26. The bushing flange overlies the surface of jaw member 30 and the bushing is retained in place by lock-washer 42 and lock-nut 28 which is screwed down over the threaded portion 40 of guide screw 27.

When the snagger plate is at rest, spring 34 acts on plug 37 whose head 38 is in contact with abutment surface 23 to bias jaw 30 inwardly such that the outer end of slot 26 is held against bushing 41 surrounding the guide screw 27. When the snagger plate begins to rotate the jaw 30 tends to move outwardly under the action of centrifugal force and, when this force is sufficient to overcome the force of spring 36 the jaw moves radially outwardly, guided by guide screw 27 in slot 26, the interaction of guide faces 22 and 32 and the outer end of jaw 30 in slot 16, until abutment surface 33 comes into contact with abutment surface 23, at which point strand engaging face 31 is a distance from strand engaging face 24, slightly less than the diameter of a strand to be snagged. Thus, a wedge like gap is formed between the fixed snagger tooth and the movable jaw member which is capable of securely retaining a strand forced therebetween. As the snagger plate rotation slows down and comes to a stop, the centrifugal force decreases and is finally eliminated and the movable jaw is drawn inwardly under the action of spring 36 to increase the gap between face 25 and face 31 and to release a strand retained therein. The curvature of the portion of the tooth overlying the flange 13 facilitates the automatic release of the strand when the gap is increased.

It is preferably that faces 24 and 31 never come into contact in order to eliminate high stresses in the outer tooth whereby to eliminate the possibility of this portion of the tooth breaking and flying outwardly as a hazard to workmen in the vicinity. This is achieved in the illustrated construction by abutment surfaces 23 and 33 which do not permit faces 24 and 31 to come into direct contact. As abutment surfaces 23 and 33 are located within the flange 13, any breakage of the tooth or jaw in this area will not result in broken pieces flying outwardly since such pieces will be trapped within the area bounded by the snagger plate, the flange and the side of the reel with which the snagger plate is associated. It is also preferable that slot 16 be of a size capable of being completely filled by tooth 20 and jaw 30 and that jaw 30 occupy the slot at all times so that no loose strand end or foreign matter can enter the slot to jam the movable jaw member and prevent it from sliding either inwardly or outwardly.

What I claim as my invention is:

1. A snagger plate for strand take-up apparatus comprising a snagging member rigidly secured to said snagger plate, a part of said snagging member extending beyond and overlying a portion of the periphery of said snagger plate, and a jaw member supported on said snagger plate and movable toward and away from said part of the snagging member between a first limiting position beyond the periphery of said snagger plate and distant from said part of the snagging member less than the diameter of a strand to be snagged, and a second limiting position distant from said part of the snagging member greater than the diameter of a strand to be snagged, said jaw member being resiliently biased toward said second limiting position and movable toward said first limiting position under the action of centrifugal force upon rotation of the snagger plate.

2. A snagger plate as defined in claim 1, wherein the movement of the jaw member is substantially radial to the snagger plate.

3. A snagger plate as defined in claim 1, wherein said snagger plate is provided with a peripheral flange, said flange being slotted for the passage of said snagging member and said jaw member therethrough.

4. A snagger plate as defined in claim 3, wherein the area of said slot is at all times substantially completely occupied by said snagging member and said jaw member.

5. A snagger plate as defined in claim 1, wherein said snagger plate is provided with an upstanding guide pin projecting from the side thereof on which said jaw member is supported, said jaw member being provided with a radially disposed slot for the receipt of said guide pin.

6. A snagger plate as defined in claim 1 including a first abutment surface rigidly secured to said plate and located in the path of movement of a second abutment surface on said jaw member whereby to define said first limiting position.

7. A snagger plate as defined in claim 6, wherein the first abutment surface on said plate is a surface of said snagging member.

8. A snagger plate for strand take-up apparatus comprising a circular plate, a plurality of snagging members rigidly secured to said plate, each of said snagging members having a tooth portion extending beyond and overlying a portion of the periphery of said plate, each of said snagging members having a guide face perpendicular to the plane of said plate and radially disposed thereof and an abutment surface perpendicular to the plane of said plate and at a right angle to said guide face, a plurality of guide pins adjacent each said snagging member, a plurality of jaw members, each adjacent one of said snagging members and movable radially of said plate between a first limiting position beyond the periphery of said circular plate and distant from said tooth portion less than the diameter of a strand to be snagged and a second limiting position distant from said tooth portion greater than the diameter of a strand to be snagged, each of said jaw members being provided with a radially disposed elongated slot for the receipt of said guide pin and having a first surface parallel with, and in sliding contact with said guide face, and a second surface parallel with, and adapted to contact said abutment surface, and resilient means biasing said second surface away from said abutment surface whereby to urge said jaw member to said second limiting position.

9. A snagger plate as defined in claim 8, wherein said circular plate is provided with a periperhal flange, said flange being provided with a plurality of peripherally disposed slots therein, each of said slots being adapted to snuggly receive one of said snagging members and one of said jaw members.

10. A snagger plate for strand tape-up apparatus comprising a circular plate having a peripheral flange, a pcripherally disposed slot therein, a snagging member rigidly secured to said plate, said snagging member having a tooth portion extending through said slot beyond and overlying a portion of said flange, an abutment surface rigidly secured to said circular plate, a jaw member adjacent said snagging member and movable radially of said plate between a first limiting position beyond the periphery of said circular plate and distant from said tooth portion less than the diameter of a strand to be snagged and a. second limiting position distant from said tooth portion greater than the diameter of a strand to be snagged, said jaw member having a surface adapted to contact said abutment surface whereby to define said first limiting position.

References Cited by the Examiner UNITED STATES PATENTS 3,051,403 9/62 Johnson 242- 3,064,912 11/62 Bittman 242-25 MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATH, Examiner. 

1. A SNAGGER PLATE FOR STRAND TAKE-UP APPARATUS COMPRISING A SNAGGING MEMBER RIGIDLY SECURED TO SAID SNAGGER PLATE, A PART OF SAID SNAGGING MEMBER EXTENDING BEYOND AND OVERLYING A PORTION OF THE PERIPHERY OF SAID SNAGGER PLATE, AND A JAW MEMBER SUPPORTED ON SAID SNAGGER PLAGE AND MOVABLE TOWARD AND AWAY FROM SAID PART OF THE SNAGGING MEMBER BETWEEN A FIRST LIMITING POSITION BEYOND THE PERIPHERY OF SAID SNAGGER PLATE AND DISTANT FROM SAID PART OF THE SNAGGING MEMBER LESS THAN THE DIAMETER OF A STRAND TO BE SNAGGED, AND A SECOND LIMITING POSITION DISTANT FROM SAID PART OF THE SNAGGING MEMBER GREATER THAN THE DIAMETER OF A STRAND TO BE SNAGGED, SAID JAW MEMBER BEING RESILIENTLY BIASED TOWARD SAID SECOND LIMITING POSITION AND MOVABLE TOWARD SAID FIRST LIMITING POSITION UNDER THE ACTION OF CENTRIFUGAL FORCE UPON ROTATION OF THE SNAGGER PLATE. 